Method of oxidative treatment of human hair

ABSTRACT

The method of oxidative treatment of human hair which comprises treating said hair with an aqueous solution of (1) water-soluble peroxyhydrates or hydrogen peroxide and (2) an activator diacylated 2,5-diketopiperazine.

United States Patent [191 Heinz et a1.

[ METHOD OF OXIDATIVE TREATMENT OF HUMAN HAIR [75] Inventors: Arnold Heinz, Hilden; Dieter Kuhling, Monheim, both of Germany [73] Assignee: Henkel& Cie GmbH,

Dusseldorf-Holthauser, Germany [22] Filed: Aug. 2, 1971 [21] App]. No: 168,404

[30] Foreign Application Priority Data 8/1l1.5; 260/268 C, 268 DK [11-] 3,812,247 [451 May 21, 1974 [56] References Cited UNITED STATES PATENTS 9/1956 Safir et a1 260/268 DK 7/1965 Edman et a1 424/62 Primary Examiner-Albert T. Meyers Assistant Examiner-Dale R. Ore Attorney, Agent, or Firm-Hammond & Littell [5 7] ABSTRACT The method of oxidative treatment of human hair which comprises treating said hair with an aqueous solution of (1) water-soluble peroxyhydrates or hydrogen peroxide and (2) an activator diacylated 2,5- diketopiperazine.

9 Claims, No Drawings METHOD OF OXIDATIVE TREATMENT OF HUMAN HAIR THE PRIOR ART Aqueous solutions of inorganic per-compounds, especially of hydrogen peroxide or perborates, have been used for a long time as oxidizing and bleaching agents for a large variety of materials. However, for practical purposes the active oxgen released by the percompounds does not act with sufficient speed. Therefore, these bleaching agents cannot be adequately used with materials such as human hair which is sensitive to temperature, and whichhas to be bleached at relatively low temperatures, except on prolonged application times.

The copending commonly assigned United States Patent application, Ser. No. 141,373, filed May 7, 1971, describes the method of oxidative treatment of human hair with aqueous solutions of per-compounds, utilizing as activator, acylated glycolurils of the formula in which at least two of the residues R to R represent acyl residues having two to eight carbon atoms, while the other residues represent hydrogen atoms and/or alkylor arylresidues with one to eight carbon atoms and/or acyl residues with two to eight carbon atoms. The acyl residues present in the molecule may be the same or different; tetraacylglycolurils with the same C acyl residues, especially tetraacetylglycoluril, are preferably used.

OBJECTS OF THE INVENTION An object of the present invention is the development of materials which will activate per-compounds, particularly at temperatures below 45C.

Another object of the invention is the development of a method of oxidative treatment of human hair which consistsessentially of contacting human hair, at a temperature of from 20C to 45C, with an aqueous liquid containing an oxidizer selected from the group consisting of water-soluble peroxyhydrates and hydrogen peroxide in an amount sufficient to supply from gm to 200 gm per liter of H 0 equivalent and from gm to 500 gm per liter of an activator diacylated 2,5- diketopiperazine having the formula wherein R and R are acyls of organic carboxylic acids having from two. to nine carbon atoms selected from the group consisting of alkanoic acids, nitriloacetic acid, haloalkanoic acids, benzoic acid, nitrobenzoic acid, halobenzoic acid,- alkylbenzoic acid, nitroalkylbenzoic acid, haloalkylbenzoic acid, alkoxybenzoic acid and nitrilobenzoic acid, and R and R are members selected from the group consisting of hydrogen, alkyl having from one to three carbon atoms, hyclroxyalkyl having one to three carbon atoms, haloalkyl having one to three carbon atoms, nitroalkyl having one to three carbon atoms, nitriloalltyl having two to four carbon atoms and alkoxyalkyl having two to five carbon atoms.

These and other objects of the invention will become more apparent as the description thereof proceeds.

DESCRIPTION OF THE INVENTION The invention relates to the use of certain organic substances as activators for per-compounds, which enable the minimum temperature needed for a practically effective bleaching and oxidative treatment of human hair to be reduced and/or the oxidation process to be accelerated.

The substances to be used as activators for the percompounds according to the invention are diacylated 2,5-diketopiperazines of the following formula I in which R, and R each represent acyl residues of organic carboxylic acids with two to nine carbon atoms, and R and R each represent hydrogen and/or an optionally substituted hydrocarbon residue with one to three carbon atoms. The acyl residues present in the molecule may be the same or different.

The said compounds are therefore used as activators for H 0 or per-compounds (peroxycompounds) yielding H 0 in water.

These activators are marked by an improved activating action compared with the known activators.

Diacyl-diketopiperazines with the same R, and R residues are easier to prepare than those with different acyl residues; therefore the former have greater practical importance. When the residues R, and R are aliphatic, they preferably contain two to four carbon atoms, and when they represent aromatic residues, they may contain up to nine carbon atoms. Consequently, the following are preferably used as the residues R and R acetyl, propionyl, nor isobutyryl, benzoyl, toluoyl or xyloyl. Suitable substituents are C alkoxy groups, halogen atoms, and nitro or nitrile groups; chloroand- /or nitro-substituted aromatic residues which are of especially practical interest are m-chloroor mor pnitro substituted residues; The residues R and R are preferably the same, for example, methyl or ethyl resigen atoms, or nitro, nitrile, methoxy or ethoxy groups.

These diacylated 2,5-diketopiperazines are therefore those having the formula wherein R and R are acyls of organic carboxylic acids having from two to nine carbon atoms selected from the group consisting of alkanoic acids, nitriloacetic acid, haloalkanoic acids, benzoic acid, nitrobenzoic acid, halobenzoic acid, alkylbenzoic acid, nitroalkylbenzoic acid, haloalkylbenzoic acid, alkoxybenzoic acid and nitrilobenzoic acid, and R and R are members selected from the group consisting of hydrogen, alkyl having from one to three carbon atoms, hydroxyalkyl having one to three carbon atoms, haloalkyl having one to three carbon atoms, nitroalkyl having one to three carbon atoms, nitriloalkyl having two to four carbon atoms and alkoxyalkyl having two to five carbon atoms. Preferred are those compounds where R, and R are the same and are acyls of alkanoic acids having two to four carbon atoms, nitriloalkanoic acids having three to four carbon atoms, haloalkanoic acids having two to four carbon atoms, benzoic acid, halobenzoic acids, nitrobenzoic acids, nitrilobenzoic acids and methoxybenzoic acids; and R and R are the same and are hydrogen or alkyl having one to three carbon atoms.

Suitable acyl residues of organic carboxylic acids having from two to nine carbon atoms are, for example, alkanoyls, such as acetyl, propionyl, butyryl, etc; haloalkanoyls, such as monobromoacetyl and preferably chloroalkanoyls such as monochloroacetyl, dichloroacetyl, trichloroacetyl, etc.; nitriloacetyl, benzoyl and toluyl which may be substituted with nitro groups or halogen atoms such as chlorobenzyl, nitrobenzoyl, chlorotoluyl and nitrotoluyl; methoxybenzoyls; and nitrilobenzoyls. Suitable alkyls having one to three carbon atoms are, for example, methyl, ethyl, etc.

Of the aceylated diketopiperazines to be used as activators according to the invention, the diacetyland dibenzoyl derivatives are known (see- Berichte der deutschen chemischen Gesellschaft, 1897, 30, page 1585 and 1921, 54, page 2691 These compounds are obtained by acylation of the diketopiperazine with the corresponding carboxylic acid anhydrides or carboxylic acid halides.

in an analogous way the diketopiperazines alkylated in the 3- and/or 6-position can be acylated. The alkylated piperazines to be used as starting materials are oba a b e assq s iwg Balkan is. a.s z t,h i m de France, 1942, pp. 487-494, by condensation of the corresponding amino acids. The 3,6-dimethyl-2,5- diketo-piperazine can be acetylated according to Recueil des Travaux Chimiques des Pays-Bas, 1908, 27, p. 205.

The following, for example, are obtainable by such processes: dipropionyl, dibutyrl, dinitriloacetyl, dimonochloroacetyl di-dichloroacetyl, ditrichloroacetyl, di-m-chlorobenzoyl, di-nitrobenzoyl,

dimethoxybenzoyl or di-nitrilobenzoyL diketopiperazine and the corresponding derivatives alkylated in the 3- and/or 6-position.

Dipropionyl-diketopiperazine is obtained, for example, by the following method: A suspension of 22.8 g. (0.2 mol) of 2,5-diketopiperazine in 350 ml. (2.7 mol) of propionic anhydride is stirred for 3 hours at 140C. After cooling, undissolved material is filtered off and the clear filtrate is evaporated in vacuo. The crude 1,4- dipropionyl-2,5-diketopiperazine thus obtained is already utilizable in this state as an activator for percompounds. However it can be purified by washing with water and isopropanol and then recrystallizing from isopropanol, a yield of 23.5 g (52.7 percent of theory) being then obtained. The melting point is 1l3-114.5C.

The analysis values calculated for the formula C H N O agree satisfactorily with the values found (C calc.: 53.09 percent, found: 53.26 percent; H calc.: 6.24 percent, found: 5.94 percent; N calc.: 12.38 percent, found: 12.49 percent; the IR, NMR and mass spectra agreed with these to be expected for 1,4- dipropionyl-2,5-diketopiperazine.

For the preparation of 1,4-dipropionyl-3,6-dimethyl- 2,5-diketopiperazine, a suspension of 28.4 g (0.2 mol) of 3,6-dimethy1-2,5-diketopiperazine in 130 g (1 mol) of propionic acid anhydride is treated with 0.5 ml of percent perchloric acid and the mixture is heated for 8 hours at C to C. The clear solution obtained is concentrated and the crude dipropionyl-dimethyldiketopiperazine obtained as residue is digested with petrol (b.p. 80100C), filtered by suction and the residue is again washed with petrol. The crude product is obtained in a yield of 14.8 g (29.3 percent of theory). The melting point lies at 106C to l 14C. 1t can be used in this state as an activator. However, after recrystallizing from isopropanol, the pure product used for analysis melts at l 13C to l 14C.

The analysis values calculated for the formula C H N Q, agreed satisfactorily with the values found (C calc: 56.68 percent, found: 56.59 percent; H calc.: 7.13 percent, found: 7.23 percent; N calc.: l 1.02 found; 11.13 percent).

The per-compounds to be activated can be any type of inorganic or organic per-compound which will release active oxygen in an aqueous solution. For economic reasons, the per-compounds preferably utilized are inorganic peroxides, inorganic per-acids, inorganic peroxyhydrates and products of the addition of hydrogen peroxide with inorganic and organic compounds.

Of the peroxides to be activated, hydrogen peroxide is of the greatest practical importance. It may be used as such, but may also be used in the form of its mostly solid peroxyhydrates or products of addition with inorganic and organic compounds. The latter include, for example, the products of addition of hydrogen peroxide to urea or melamine, and examples of the peroxyhydrates and the perborates, perortho-, perpyro-, and perpoly-phosphates, percarbonates and persilicates. These peroxyhydrates are preferably soluble in water and are ordinarily utilized in the form of their alkali metal salts, such astheir sodium salts. The activators according to the invention, however, may also be used together with true per-acids, such as for example, Caros acid (peroxymonosulfuric acid, H 50 or peroxydisulfuric acid (H S O or their salts.

Each acyl residue present in the activator is able to activate an active oxygen atom of the per-compound used. Theoretically, therefore, one molecule of a diacylated 2,5diketopiperazine is in a position to activate 2 oxygen atoms. In practice, however, satisfactory effects are attained in many cases even with substantially smaller amounts of activator, while on the other hand, the activator may also be used in relatively large excess. in general, the amount of activator used is chosen so that 0.5 to 6,-preferably 0.75 to 3 acyl residues are present per active oxygen atom.

The acceleration of the bleaching and oxidizing processes on human hair is shown at low temperatures in the range from 20C to 45C, and preferably from 20C to 37C and more, particularly from 20C to 30C. Depending upon the problem to be solved, it is possible for the technician, when using the activators according to the invention, either'to reduce the temperature of treatment and/or to shorten the time of treatment, the temperature remaining the same.

The conditions to be maintained during operation with the activators according to the invention, such as for example, the concentration of the peroxide, temperature, pH value and time of treatment, depend substantially on the color of the hair to be oxidized and/or bleached and the brightness of the desired color tone if an oxidative dyestuff is employed. The usually aqueous oxidizing or bleaching liquids may contain gm to 200 gm, preferably gm to 100 gm, per liter of H 0 equivalent and have a pH value from 7 to l l, and especially from 8 to l0.5.

As previously stated, aqueous solutions of percompounds and diacylated 2,5-diketopiperazine activators, optionally with other ingredients as indicated below may be utilized. These aqueous solutions preferably contain sufficient per-compounds to give a concentration of from 20 mg to 500 mg, preferably 50 mg to 250 mg per liter of active oxygen and sufficient diacylated 2,5-diketopiperazine activators to provide from 0.5 to 6, preferably 0.75 to 3 acyl residues of the diacylated 2,5-diketopiperazine per active oxygen atoms and preferably from 20 gm to 500 gm per liter of the diacylated 2,5-diketopiperazine.

The activators, according to the invention, may be used wherever per-compounds, especially hydrogen peroxide or perborates, have previously been used as oxidizing and/or bleaching agents for the oxidative treatment of human hair, preferably living human hair.

The desired pl-l-value is adjusted by addition of neutralor alkaline-reacting substances, possibly by buffer mixtures, and particularly by additives which have also been co-employed in a corresponding, formerly customary, treatment.

These frequently include the surface-active substances which serve to decrease the surface tension of the aqueous oxidizing or bleaching liquid, such as for example, soap or known synthetic detergents of anionic, non-ionic or amphoteric nature. When working in the alkaline range, alkaline substances may be added as well as inorganic or organic complex-forming compounds, especially complex-forming compounds suitable for binding the so-called hardness-producing substances in water or heavy metals which may possibly be present.

The following examples are illustrative of the practive of the invention without, however, being limitative in any manner.

EXAMPLES l, 2 and 3 The usefulness of the activators according to the invention was demonstrated by the following experiments:

An aqueous solution which contained 0.615 gm of N Q2 -H.2-.:4-3. 2O (4m O d 2:51.!!! f N23 0 l0l-l O per liter, after addition of 4 mMol of activator, was heated to 45 and maintained at the said temperature with stirring during the whole experiment. At certain intervals of time, ml samples were removed by pipette, immediately added to a mixture of 250 gm of ice and 15 ml of glacial acetic acid, and then, after addition of about 0.35 gm of potassium iodide, were titrated with 0.1 N sodium thiosulfate solution using starch as an indicator.

Under the experimental conditions indicated, 8.0 ml of thiosulfate solution were consumed with a 100 percent activation of the peroxy-compound used. The thiosulfate consumed and the percentage amount of activated peroxycompound are given in the Tables I, II and Ill. Table for Example l:

TABLE 1 Activation of perborate with l,4-diacetyl-2,5-diketopiperazine Activation of perborate with. l,4-dipropionyl-2 ,5-diketopiperazine Sample taken Activation obtained at 45C after x minutes ml O 0.1N Na,S,O activated x l 7.46 92.1 5 7.15 88.3 10 7.07 87.3 15 6.9l 85.3 30 6.53 80.6 60 5.78 71.3

Blank Test 8.10 100 Table for Example 3 TABLE III Activation of perborate with l,4-dlacetyl-3,6-dimethyl-2,S-diketopiperazine Sample taken Activation obtained at 45C after x minutes ml %0 0.lN m s o, activated TABLE Ill-Continued Activation of perborate with 1.4-diacetyl-3,6-dimethyl-2,5-diketopiperazine Content of active oxygen of the test solutions before addition of the activator.

As may be seen, on use of the diacetylor dipropionyl-diketopiperazine the maximum degree of activation is already reached after a period of one minute, and this is maintained over a certain length of time, irrespective of the temperature. The subsequent falling off of the values is due to the spontaneous decomposition of the first formed peracetic acid or perpropionic acid. In the case of diacetyldimethyl-diketopiperazine, the amount of activated oxygen slowly rises in the course of the experiment. The products therefore difi'er in the period of activation per unit of time and it is possible to choose an activator, the action of which is optimal to the bleaching or oxidizing process in question.

These solution can be used as oxidizing and bleaching liquids over a wide temperature range, and they have also good antimicrobial properties.

If only 0.5 mol of activator is used per gram-atom of active oxygen in the described experiments, a smaller activation is indeed obtained, but for many technical purposes it is completely satisfactory.

EXAMPLE 4 For the bleaching of human hair, the dyeing of hair by means of oxidation dyestuffs, and the oxidative treatment of hair after setting by the action of reducing thio-compounds (cold wave process), aqueous solutions containing 10 gm to 200 gm of H per liter are normally used. When this treatment was carried out after addition of 20 gm to 500 gm per liter of diacetylor dipropionyl-diketopiperzine, a considerable intensifying of the oxidizing action of the H 0 was observed, so that, if desired, smaller concentration of H 0 could also be used.

EXAMPLE 5 Solutions which contained 630 mg/l of a commercial sodium perborate tetrahydrate was about 94 percent by weight active oxygen (4 mg-atom/l active oxygen) and 2.5 gm/l Na P O 10 H O, were, after addition of 792.8 mg/] diacetyl-diketopiperazine (4 mMol/l corresponding to 2 acetyl radical per active oxygen), kept at 20C under constant stirring. In definite time periods 100 ml were pipetted off, immediately put on a mixture of 250 gm ice and ml glacial acetic acid and subsequently, after addition of about 0.35 gm potassium iodide, titrated with 0.1 N sodium thiosulfate solution and starch as indicator. The pH of this solution, measured immediately after addition of the diacetyldiketopiperazine, was 10.15; in two parallel experiments solutions were processed whose pl-l-values were adjusted by the addition of borate and hydrochloric 8 acid, or of boric acid, potassium chloride and sodium hydroxide to 8.15 and 9.93.

Under the experimental conditions indicated for a 100 percent activation of the peroxy-compound used about 8.0 ml thiosulfate solution are consumed. In Table IV the percent activation is calculated from the theoretical maximum consumption and the actual use of thiosulfate solution.

TABLE IV Sample taken oxygen activated at 20C after x minutes activator: diacetyl-diketopiperazine pH=10.15 pH=8.15 pH=9.93

From the above and Table I, it can be seen that the extent of activation is dependent upon the pH, the temperature and the amount of the activator used.

EXAMPLE 6 For the bleaching of living human hair, for the dyeing of hair with the aid of oxidation dyes and for the oxidative treatment of hair after setting by the action of reducing thio-compounds, an aqueous solution is used which is prepared in the following way:

six gm of (NH SO 15 m1 of a 25 percent aqueous NH 37 ml of a 30% H 0 were dissolved in 30 ml of water and sufficient water is added to give 100 ml.

When such a solution is used for the lightening of dark-blond hair, at 20 to 30C within 30 to minutes a noticeable lightening is attained. If, however, 40 gm of diacetyl-diketopiperazine are added, the hair is in the same times substantially lightened. In addition, the time of treatment can also be shortened.

1f the equivalent amount of l,4-diacetyl-3,6- dimethy1-2,5-piperazine is used, the bleaching activation is less at the start of the treatment. It is thus easier to attain only a partial lightening of the color tone up to a definite, desired color tone.

The preceding specific embodiments are illustrative of the practice of the invention. It is obvious, however, that other expedients known to those skilled in the art may be employed without departing from the spirit of the invention.

We claim:

1. A method of oxidative treatment of human hair which consists essentially of contacting human hair, at a temperature of from 20C to 45C, with an aqueous liquid containing an oxidizer selected from the group consisting of water-soluble peroxyhydrates and hydrogen peroxide in an amount sufficient to supply from 10 gm to 200 gm per liter of H 0 equivalent and from 20 gm to 500 gm per liter of an activator diacylated 2,5- diketopiperazine having the formula acid, haloalkanoic acids, benzoic acid, nitrobenzoic acid, halobenzoic acid, alkylbenzoic acid, nitroalkylbenzoic acid, halolkylbenzoic acid, alkoxybenzoic acid and nitrilobenzoic acid, and R and R are members selected from the group consisting of hydrogen, alkyl having from one to three carbon atoms, hydroxyalky] having one to three carbon atoms, haloalkyl having one to three carbon atoms, nitroalkyl having one to three carbon atoms, nitriloalkyl having two to four carbon atoms and alkoxyalkyl having two to five carbon atoms.

2. The method of claim 1 wherein said aqueous liquid has a pH offrom 7 to 11.

3. The method of claim 2 wherein said aqueous liquid has a pH of from 8 to 10.5.

4. The method of claim 1 wherein said temperature isfrom ZO Q to 30C.

5. The method of claim 1 wherein said activator diacylated '2,5-diketopiperazine is l,4-diacetyl-2,5-

. diketopiperazine.

6. The method of claim 1 wherein said activator diacylated 2,5-diketopiperazine is l,4-dipropionyl2,5- diketopiperazine.

7. The method of claim 1 wherein said activator diacylated 2,5-diketopiperazine is l,4-diacetyl-3,6- dimethyl-2,5-diketopiperazine.

8. The method of claim 1 wherein said diacylated 2,5-diketopiperazine is added to said aqueous liquid in an amount sufficient that from 0.5 to 6 acyls in said diacylated 2,5-diketopiperazine are present per active oxygen atom in said aqueous solution.

9. The method of claim 1 wherein said temperature is from 20C to 37C, and said human hair is living human hair.

Patent No. 3 812 2 1? Inventor(s) Dated May 2l l9? ARNOLD HEINS and II'TETE' K JELING d It is certified that error appears in the above-identified patent an that said Letters Patent are hereby corrected as shown below:

Patent Appln. Col. Line Page Line Heading Declaration Heading Assignment Heading Declaration Claim 1 3 Llaim l 5 Claim 5 9 1 Claim 1) (10) First inventor's name should read Hein s "Dusseldorf Holthauser should read. ---Dusseldorf-Holthausen-.

Priority number shouldread l "aceylated should read -acy1ated-- "Berichte" should read -Ber i c hter I "found;" shou d read '-found "2.5piperazine" should read --2.5-diketo-piperazine-.

"with an aqueous" should read -with an effective amount of an aqueous-- "consisting of later-soluble" should I read --consisting of a water. soluble- "peroxyhydrates". should read -'-peroxyhydrate-- "wherein R and R are acyls of organic carboxylic acids should read Page 2 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 5, -7 Dated May 21 l97 L Inventor) Arnold Heins and Dieter Kuhling It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

"alkanoic acids" should read 3 Cla im l) (12) --alkano1c acid-- 9 14 I y 3 "haloalkanoic acids" should read Claim 1) (l3) --haloalkanoic acid- 9 7 members should be deleted. Claim 1) (16) claim 8 2 v A "is added" should read --*is ,presentclaim 8 2 I "to said aqueous liquid" should be deleted Claim 8 5 1 "solution" should read --lig uid Signed and sealed this 3rd day of June 1975.

(SEAL) Attest:

C. MARSHALL DANN RUTH C. MASON Commissioner of Patents Attesting Officer and Trademarks 

2. The method of claim 1 wherein said aqueous liquid has a pH of from 7 to
 11. 3. The method of claim 2 wherein said aqueous liquid has a pH of from 8 to 10.5.
 4. The method of claim 1 wherein said temperature is from 20*C to 30*C.
 5. The method of claim 1 wherein said activator diacylated 2,5-diketopiperazine is 1,4-diacetyl-2,5-diketopiperazine.
 6. The method of claim 1 wherein said activator diacylated 2,5-diketopiperazine is 1,4-dipropionyl-2,5-diketopiperazine.
 7. The method of claim 1 wherein said activator diacylated 2,5-diketopiperazine is 1,4-diacetyl-3,6-dimethyl-2,5-diketopiperazine.
 8. The method of claim 1 wherein said diacylated 2,5-diketopiperazine is added to said aqueous liquid in an amount sufficient that from 0.5 to 6 acyls in said diacylated 2,5-diketopiperazine are present per active oxygen atom in said aqueous solution.
 9. The method of claim 1 wherein said temperature is from 20*C to 37*C, and said human hair is living human hair. 